This is still true today, and tap changers are designed following this approach. As this is a tap changer that operates under a transformer full load condition, the circuit should never be broken.

A load tap changer (LTC) is a critical component in electrical power systems, enabling efficient and reliable power distribution by regulating voltage levels in response to fluctuating demand.

Abstract: IN THE DESIGN of load tap changer mechanisms for large power and regulating transformers, the possibility of their operation during system short-circuits is an important design consideration ...

Abstract: With the growing demand for precise voltage adjustment and reactive regulation, the frequent operation of on-load tap changers (OLTCs) in oil-immersed systems has led to increased erosion of ...